小编给大家分享一下MySQL分区表如何实现按月份归类,相信大部分人都还不怎么了解,因此分享这篇文章给大家参考一下,希望大家阅读完这篇文章后大有收获,下面让我们一起去了解一下吧!建表一般的表(innodb)创建后只有一个 idb 文件:cre
小编给大家分享一下MySQL分区表如何实现按月份归类,相信大部分人都还不怎么了解,因此分享这篇文章给大家参考一下,希望大家阅读完这篇文章后大有收获,下面让我们一起去了解一下吧!
一般的表(innodb)创建后只有一个 idb 文件:
create table nORMal_table(id int primary key, no int)
normal_table.ibd
创建按月份分区的分区表,注意!除了常规主键外,月份字段(用来分区的字段)也必须是主键:
create table partition_table(id int AUTO_INCREMENT, create_date date, name varchar(10), primary key(id, create_date)) ENGINE=INNODB DEFAULT CHARSET=utf8 partition by range(month(create_date))(partition quarter1 values less than(4),partition quarter2 values less than(7),partition quarter3 values less than(10),partition quarter4 values less than(13));
查看数据库文件:
partition_table#p#quarter1.ibd partition_table#p#quarter2.ibd partition_table#p#quarter3.ibd partition_table#p#quarter4.ibd
insert into partition_table(create_date, name) values("2021-01-25", "tom1");insert into partition_table(create_date, name) values("2021-02-25", "tom2");insert into partition_table(create_date, name) values("2021-03-25", "tom3");insert into partition_table(create_date, name) values("2021-04-25", "tom4");insert into partition_table(create_date, name) values("2021-05-25", "tom5");insert into partition_table(create_date, name) values("2021-06-25", "tom6");insert into partition_table(create_date, name) values("2021-07-25", "tom7");insert into partition_table(create_date, name) values("2021-08-25", "tom8");insert into partition_table(create_date, name) values("2021-09-25", "tom9");insert into partition_table(create_date, name) values("2021-10-25", "tom10");insert into partition_table(create_date, name) values("2021-11-25", "tom11");insert into partition_table(create_date, name) values("2021-12-25", "tom12");
select count(*) from partition_table;> 12 查询第二个分区(第二季度)的数据:select * from partition_table PARTITION(quarter2);4 2021-04-25 tom45 2021-05-25 tom56 2021-06-25 tom6
当删除表时,该表的所有分区文件都会被删除
核心的两个存储过程:
auto_create_partition为创建表分区,调用后为该表创建到下月结束的表分区。
auto_del_partition为删除表分区,方便历史数据空间回收。
DELIMITER $$DROP PROCEDURE IF EXISTS auto_create_partition$$CREATE PROCEDURE `auto_create_partition`(IN `table_name` varchar(64))BEGIN SET @next_month:=CONCAT(date_format(date_add(now(),interval 2 month),'%Y%m'),'01'); SET @sql = CONCAT( 'ALTER TABLE `', table_name, '`', ' ADD PARTITION (PARTITION p', @next_month, " VALUES LESS THAN (TO_DAYS(", @next_month ,")) );" ); PREPARE STMT FROM @SQL; EXECUTE STMT; DEALLOCATE PREPARE STMT;END$$DROP PROCEDURE IF EXISTS auto_del_partition$$CREATE PROCEDURE `auto_del_partition`(IN `table_name` varchar(64),IN `reserved_month` int)BEGIN DECLARE v_finished INTEGER DEFAULT 0; DECLARE v_part_name varchar(100) DEFAULT ""; DECLARE part_cursor CURSOR FOR select partition_name from information_schema.partitions where table_schema = schema() and table_name=@table_name and partition_description < TO_DAYS(CONCAT(date_format(date_sub(now(),interval reserved_month month),'%Y%m'),'01')); DECLARE continue handler FOR NOT FOUND SET v_finished = TRUE; OPEN part_cursor;read_loop: LOOP FETCH part_cursor INTO v_part_name; if v_finished = 1 then leave read_loop; end if; SET @SQL = CONCAT( 'ALTER TABLE `', table_name, '` DROP PARTITION ', v_part_name, ";" ); PREPARE STMT FROM @SQL; EXECUTE STMT; DEALLOCATE PREPARE STMT; END LOOP; CLOSE part_cursor;END$$DELIMITER ;
下面是示例
-- 假设有个表叫records,设置分区条件为按end_time按月分区DROP TABLE IF EXISTS `records`;CREATE TABLE `records` ( `id` int(11) NOT NULL AUTO_INCREMENT, `start_time` datetime NOT NULL, `end_time` datetime NOT NULL, `memo` varchar(128) CHARACTER SET utf8mb4 NOT NULL, PRIMARY KEY (`id`,`end_time`)) PARTITION BY RANGE (TO_DAYS(end_time))( PARTITION p20200801 VALUES LESS THAN ( TO_DAYS('20200801')));DROP EVENT IF EXISTS `records_auto_partition`;-- 创建一个Event,每月执行一次,同时最多保存6个月的数据DELIMITER $$CREATE EVENT `records_auto_partition`ON SCHEDULE EVERY 1 MONTH ON COMPLETION PRESERVEENABLEDOBEGINcall auto_create_partition('records');call auto_del_partition('records',6);END$$DELIMITER ;
几点注意事项:
存储过程中,DECLARE 必须紧跟着BEGIN,否则会报看不懂的错误
游标的DECLARE需要在定义声明之后,否则会报错
如果是自己安装的Mysql,有可能Event功能是未开启的,在创建Event时会提示错误;修改my.cnf,在 [mysqld] 下添加event_scheduler=1后重启即可。
以上是“MySQL分区表如何实现按月份归类”这篇文章的所有内容,感谢各位的阅读!相信大家都有了一定的了解,希望分享的内容对大家有所帮助,如果还想学习更多知识,欢迎关注编程网数据库频道!
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